The present disclosure is related to the testing of drilling fluids and, more particularly, to an apparatus and method for evacuating part of a fluid loss characteristics test system.
In drilling wellbores in the oil and gas industry, drilling fluid or “mud” is typically circulated into and out of the wellbore. The drilling fluid serves several purposes, such as lubricating the drill bit, cooling the drill bit, and removing the cuttings from the wellbore as the drill bit advances into the rock formation. To accomplish its intended purposes, the drilling fluid should ideally possess certain characteristics. For example, if desired, the drilling fluid should be capable of depositing a coating on the wall of the wellbore being drilled, the coating being commonly referred to as a filter cake. The filter cake serves to stabilize the wellbore and also prevent loss of the liquid portion of the drilling mud through the walls of the borehole into the adjoining rock formations. This loss of liquid from the drilling fluid is commonly referred to as fluid loss and encompasses a function of many variables such as the composition of the drilling fluid, the types of rock formations encountered while drilling, temperatures and pressures in the borehole, etc.
In order to ensure that a certain drilling fluid is able to operate as required or intended, drilling fluids are often tested under simulated borehole conditions in an attempt to determine characteristics of the drilling fluid, such as potential fluid loss. Common drilling fluid testing systems, however, require time-consuming disassembly and cleaning following each testing procedure.